Fast 1-2 Shift Grind....Drivetrain Movement or Synchros?

[CYANiDE]

Hey guys,

2012 STI, 26k miles (purchased used completely stock with 14k miles).

Mods:
Cobb SF + Ceir E-tune via AP v3
SPT Catback
SPT Short Shifter + Holy Shift Kit

Now, the STi is my first manual transmission car. Purchased last summer. I drove it like a baby while I learned how to shift, rev-match, etc. Not I'm trying to learn how to drive it closer to its limits. What I can not do is a quick 1-2 upshift. No matter what I do if I try to push it into 2nd it will grind (clutch pedal still pressed in) almost as if the synchro was going bad. I do notice a lot of drivetrain movement when I WOT in 1st. If I wait a second for the revs to drop it will pop into 2nd perfectly fine.

I've seen some youtube vids of guys at the drag strip and they shift into 2nd pretty damn fast.

Is this a result of a shotty synchro, too much drivetrain movement causing something to not line up properly, or just normal behavior?

Thanks for any advice.

 

[Alin]

Did you change trans and rear diff fluids yet?

 

[CYANiDE]

Fluids were changed at 23k so they are pretty fresh.

 

[Alin]

Ok then the next thing i would take a look at are the tranny mounts and pitch stop. Make sure all of the tranny support is there.

Do you know if the car was beat on by the first owner?

 

[Batmobile_Engage]

I don't know about the 2012's, but I used to have problems getting into 3rd gear
under heavy load due to drivetrain movement. I added a Group N tranny mount and
pitch stop which seems to have almost completely eliminated this issue. Now I just
need to get the shifter bushing installed. :lol:

 

[CYANiDE]

Ok then the next thing i would take a look at are the tranny mounts and pitch stop. Make sure all of the tranny support is there.

Do you know if the car was beat on by the first owner?

As far as I can tell he didn't. The original tires still had plenty of meat on them. Red light was set to 5000, and he was an "older" guy.

I don't know about the 2012's, but I used to have problems getting into 3rd gear
under heavy load due to drivetrain movement. I added a Group N tranny mount and
pitch stop which seems to have almost completely eliminated this issue. Now I just
need to get the shifter bushing installed. :lol:

I just went during my lunch break and it seems like the tranny is shifting a lot on that shift. I'm going to order Motor/Trans mounts and probably a pitch stop and crossmember bushings while I'm at it.

 

[Boogieman98]

I had the same problem before I changed the motor mounts. Have not had the issue since

 

[HolyCrapItsFast]

Do you know what fluid you used? These drivetrains are extremely fussy about what oil and brand you use and mine had similar issues. Read the manual and use only the recommended type and weight oil. I have found Motul to be the best for STi transmissions. Others suggest Lucas, AMSoil or Redline and you can't go wrong with OEM.

 

[Batmobile_Engage]

If all else fails, maybe try the Grimmspeed "Tranny Cocktail". Some people find that it eliminates all grinding
and some notice no difference. Just a thought if you get desperate.

 

[CYANiDE]

I only use Motul fluids in my car. I honestly think its a combo of rev hang and soft bushings in the motor/trans mounts.